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The Single UNIX &reg; Specification, Version 2<br>
Copyright &copy; 1997 The Open Group

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<h4><a name = "tag_001_014_2372">&nbsp;</a>NAME</h4><blockquote>
tsort - topological sort
</blockquote><h4><a name = "tag_001_014_2373">&nbsp;</a>SYNOPSIS</h4><blockquote>
<pre><code>

tsort <b>[</b><i>file</i><b>]</b>
</code>
</pre>
</blockquote><h4><a name = "tag_001_014_2374">&nbsp;</a>DESCRIPTION</h4><blockquote>
The
<i>tsort</i>
utility
writes to standard output a totally ordered list of items
consistent with a partial ordering of items
contained in the input.
<p>
The input consists of pairs of items (non-empty strings)
separated by blanks.
Pairs of different items indicate ordering.
Pairs of identical items indicate presence, but not ordering.
</blockquote><h4><a name = "tag_001_014_2375">&nbsp;</a>OPTIONS</h4><blockquote>
None.
</blockquote><h4><a name = "tag_001_014_2376">&nbsp;</a>OPERANDS</h4><blockquote>
The following operand is supported:
<dl compact>

<dt><i>file</i><dd>A pathname of a text file to order.
If no
<i>file</i>
operand is given, the standard input is used.

</dl>
</blockquote><h4><a name = "tag_001_014_2377">&nbsp;</a>STDIN</h4><blockquote>
The standard input is a text file that is used if no
<i>file</i>
operand is given.
</blockquote><h4><a name = "tag_001_014_2378">&nbsp;</a>INPUT FILES</h4><blockquote>
The input file named by the
<i>file</i>
operand is a text file.
</blockquote><h4><a name = "tag_001_014_2379">&nbsp;</a>ENVIRONMENT VARIABLES</h4><blockquote>
The following environment variables affect the execution of
<i>tsort</i>:
<dl compact>

<dt><i>LANG</i><dd>Provide a default value for the internationalisation variables
that are unset or null.
If
<i>LANG</i>
is unset or null, the corresponding value from the
implementation-dependent default locale will be used.
If any of the internationalisation variables contains an invalid setting, the
utility will behave as if none of the variables had been defined.

<dt><i>LC_ALL</i><dd>
If set to a non-empty string value,
override the values of all the other internationalisation variables.

<dt><i>LC_CTYPE</i><dd>
Determine the
locale for the interpretation of sequences of bytes of text data as
characters (for example, single- as opposed to multi-byte characters
in arguments and input files).

<dt><i>LC_MESSAGES</i><dd>
Determine the locale that should be used to affect
the format and contents of diagnostic
messages written to standard error.

<dt><i>NLSPATH</i><dd>
Determine the location of message catalogues
for the processing of
<i>LC_MESSAGES .
</i>
</dl>
</blockquote><h4><a name = "tag_001_014_2380">&nbsp;</a>ASYNCHRONOUS EVENTS</h4><blockquote>
Default.
</blockquote><h4><a name = "tag_001_014_2381">&nbsp;</a>STDOUT</h4><blockquote>
The standard output is a text file consisting of the order list
produced from the partially ordered input.
</blockquote><h4><a name = "tag_001_014_2382">&nbsp;</a>STDERR</h4><blockquote>
Used only for diagnostic messages.
</blockquote><h4><a name = "tag_001_014_2383">&nbsp;</a>OUTPUT FILES</h4><blockquote>
None.
</blockquote><h4><a name = "tag_001_014_2384">&nbsp;</a>EXTENDED DESCRIPTION</h4><blockquote>
None.
</blockquote><h4><a name = "tag_001_014_2385">&nbsp;</a>EXIT STATUS</h4><blockquote>
The following exit values are returned:
<dl compact>

<dt>0<dd>Successful completion.

<dt>&gt;0<dd>An error occurred.

</dl>
</blockquote><h4><a name = "tag_001_014_2386">&nbsp;</a>CONSEQUENCES OF ERRORS</h4><blockquote>
Default.
</blockquote><h4><a name = "tag_001_014_2387">&nbsp;</a>APPLICATION USAGE</h4><blockquote>
The
<i>LC_COLLATE</i>
variable need not affect the actions of
<i>tsort</i>.
The output ordering is not lexicographic,
but depends on the pairs of items given as input.
</blockquote><h4><a name = "tag_001_014_2388">&nbsp;</a>EXAMPLES</h4><blockquote>
The command:
<pre>
<code>
tsort &lt;&lt;EOF
a b c c d e
g g
f g e f
h h
EOF
</code>
</pre>
<p>
produces the output:
<pre>
<code>
a
b
c
d
e
f
g
h
</code>
</pre>
<p>
</blockquote><h4><a name = "tag_001_014_2389">&nbsp;</a>FUTURE DIRECTIONS</h4><blockquote>
None.
</blockquote><h4><a name = "tag_001_014_2390">&nbsp;</a>SEE ALSO</h4><blockquote>
None.
</blockquote><hr size=2 noshade>
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Copyright &copy; 1997 The Open Group
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